I use a Rohde FSU. But I did not question the accuracy of your test equipment. I questioned your credibility by proclaiming that this CB amplifier is clean by only reporting 3rd order IMD figures.
If you do want to make a claim that any amplifier is clean based on 2 tone measurements, you could do your credibility some good by publishing all the levels of all the measured IMD products on different frequencies.
Anyone can cherry picky the best IMD results and make wild claims about the performance.
There seems to be a growing trend from CB hams wanting too promote these rubbish amplifiers for ham radio use and I see that you are very active in promoting this brand on various forums and reviews.
When I see data that is lacking is details and claims made that the amp is clean with no data to support this claim I have a right to question your assertion that this amp is clean.
I know that you have a RF Engineering background Mike, so the last thing that I want to do is give you lectures on your profession. However I dont agree that this amplifier is clean because even
at the low power that you measured the amp at, the higher products above the 9th order are from acceptable. These are the products that cause other operators on the band more grief than the 3rd
order products that are close to the nominal occupied bandwidth. Look at the FCC Part 80 Rules for the maritime HF service. The IMD mask places more emphasis on the higher order product suppression than
the the 3rd order products. The Part 80 rules for maritime HF service would be a good test of amplifier linearity for the ham radio service. Most transceivers would fail purely because their high order suppression products are so poor.
I wont change my views because I have measured the HLA300 using a R&S real time spectrum analyzer when used with a Icom 706 MK2g, anybody using this combination will be splattering because of poor IMD suppression
and ALC overshoot. Everyone of these amplifiers that I have heard on the ham bands causes excessive amount of splatter that makes operating anywhere less that 10khz away very difficult. If you have to operate this far away from any SSB station that stations signal is filthy, and in the case of RM Italy amplifiers on the ham bands this is norm.
My three main spactrum analyzers are:
What are you using?